The hithereto-known techniques for production of thready or filamentous products from curdlan include the process in which an alkaline solution of curdlan is extruded from a spinneret nozzle into an acid bath to obtain thread-like gels (Japanese Patent Publication No. 16618/1973), the process in which a certain mixture of protein and curdlan preadjusted to pH 9 to 13.5 is extruded through a nozzle into an acid coagulation bath to give a qualitatively improved edible protein fiber in filamentous form (Japanese Patent Publication No. 34227/1973) and a process for continuous production of curdlan fiber which comprises extruding a solution of curdlan in water containing sodium hydroxide or potassium hydroxide continuously into a sulfuric acid or hydrochloric acid bath supplemented with alcohol or acetone and taking up the filamentous gels under tension (Japanese Patent Publication No. 29527/1987).